Division 2.1 (flammable gas) materials transported in Specification 106A or 110A multi-unit car tanks must be stowed on deck only, and must be protected from sources of heat.
CFR 49-176.230-2013 history
2013CFR 49-176.230-2013 Transportation. Part176:Carriage by vessel. Section176.230:Stowage of Division 2.1 (flammable gas) materials.